Yes, deep and sharp (highly angled) V's tend to cushion the landing
somewhat. Also helps if the are concave. On my plane and all the other
pontoon type aircraft that I know of, the first thing that will break
is a strut. The breakpoint varies, sometimes it's the vertical strut,
sometimes the horizontal (on my plane it is known to be the vertical
strut). The Lakes don't have struts and since the fuselage is also the
hull, it IS stronger and can take more. But.... when Lakes breakup
(there is a video), it is CATASTROPHIC, they really come apart. On my
aiplane, usually if one strut breaks you can limp in to shore. If both
front struts break, and the broken part doesn't settle on the fitting
(they break at the lower fitting), you are hosed. You will go over
frontwards, maybe not capsize, but the plane can no longer taxi, the
prop cuts the floats etc. Bad scene. But sometimes the broken piece
settles on the fitting and you can limp to shore even with 2 or more
struts broken. The biggest problem is judging just how big and steep a
wave you can land on, also depends on how close together they are.
There isn't any helpful info in the POH, that I've ever seen. And it IS
a problem. Especially with straight floats. They can't circle forever
and have to go ahead and land. In this respect the amphib gives you the
option of landing on land. So then pilots try and land close to shore
to take advantage of the lee of the trees and run into the associated
hazards of wind shear and landing close to shore, running into rocks
etc. If those waves look too big, and if in doubt, don't. Pretty easy
to break a strut. The hulls themselves seem to take it fine, seldom
dent a hull from landing on a wave, at least not that I have heard of
or seen. Probably possible though. You might just loosen rivets, I
suspect.

Landing on big swells in another matter altogether. I am talking about
waves that you see on a typical lake, maybe one foot high and 20 to 75'
apart. Ocean swells are MUCH further apart and can be much larger. But
even the big planes made to land on the ocean, Grummans and the other
Navy WWII one (can't remember its id), can get into waves and swells
they can't handle.